1. Field of the Invention
The present invention relates to a maximum likelihood sequence detector for decoding linear cyclic error correction codes. More particularly, the present invention decoder is adapted to decode linear cyclic error correction codes employing cyclic correlators instead of matched filters.
2. Description of the Prior Art
Matched filter decoders have been designed to match the signal that is being decoded. When a very large number of codewords are employed in a code set, it has been necessary to provide a matched filter for each of the codewords in the code set. It is known that the number of matched filters in a decoder can be reduced by a factor of two by using the complementary property of the code.
Serial correlators are known and commercially available. Such commercially available serial correlators will continuously examine a bit stream and compare it with a reference bit stream. The comparison value or the score is accumulated over a time period which is usually one word time. When a complete code set of codewords are being decoded employing serial correlators, it has been necessary to provide half the number of serial correlators as there are codewords in the code set similar to the aforementioned matched filters.
It is often desirable to employ a code set having a large number of codewords. However, the amount of hardware necessary to decode a large number of codewords may become a limiting factor in the choice of the set of codewords. Heretofore, known decoders have not employed less than half the number of matched filters or serial correlators as there are codewords in a code set to decode linear cyclic codes.
It would be desirable to provide a new and efficient decoder for decoding linear cyclic codes which is simpler and more efficient than decoders known in the prior art.